The present invention relates to a method for fabricating a semiconductor component and to a semiconductor component.
Although the problem area of the present invention is described below on the basis of a so-called crownlike capacitor device of a semiconductor memory, the present invention is not restricted thereto, but rather relates generally to a method for fabricating semiconductor components.
A semiconductor memory has a multiplicity of memory cells each comprising at least one capacitor and a transistor. A binary information item is stored as a quantity of charge in the capacitor. Access to the quantity of charge and thus the information by means of read-out and/or writing devices of the semiconductor memory is effected via the transistor of the memory cell, which is addressed by means of word and bit lines of the semiconductor memory. In order to provide semiconductor memories having a high storage density and thus a high number of memory cells on an acceptable area, the smallest possible lateral dimensions of the memory cells, that is to say both of the transistors and of the capacitors, are required.
The operation of the memory cells requires a minimum quantity of charge that can be stored in the capacitor. The quantity of charge that can be stored is substantially determined by the area content of capacitor areas of the capacitors. Therefore, provision of sufficiently large capacitance areas is to be ensured despite the reduction of the lateral dimensions.
U.S. Pat. No. 5,652,165 describes such a capacitor having a so-called crown-shaped capacitor. The crown-shaped capacitor has at least one first cup-shaped electrode having inner surfaces and outer surfaces opposite to the inner surfaces, which run perpendicular to a semiconductor substrate. The inner and also the outer surfaces are completely covered by a dielectric, on which the second electrode is applied. A capacitor area of the crown-shaped capacitor thus essentially comprises both the inner, and also the outer, perpendicularly running surface.
A generally known fabrication method for the crown-shaped capacitor firstly requires the provision of the cup-shaped first electrode having uncovered inner and outer surfaces. In this case, the first electrode has only a low mechanical stability at this point in time in the method for fabricating the crown-shaped capacitor. In particular, this is the case when the first electrode has a substantially larger vertical dimension than horizontal dimension in order, as required previously, to provide a large capacitor area in conjunction with a small lateral space requirement.
For the fabrication of the first electrodes, liquids are used, inter alia for etching and/or cleaning the first electrode. On account of the liquids between adjacent first electrodes, a capillary force acts on said adjacent first electrodes in such a way that upper sections of the adjacent first electrodes approach one another. Since the first electrodes have only a low mechanical stability, the first electrodes can approach one another to such an extent that they actually touch one another. This is one of several possible effects on account of which the first electrodes approach one another. Adhesive effects, for example on account of electrostatic charges, prevent first electrodes, once touching one another, from being released from one another again even if the liquids are removed and the capillary force is no longer acting. This leads to desirable electrical contact-making between the adjacent first electrodes and possibly to short circuits during operation of the memory device.